Class XRFaceSubsystem

An abstract class that provides a generic API for low-level face tracking features.

Inheritance
Object
Subsystem
Subsystem<XRFaceSubsystemDescriptor>
XRSubsystem<XRFaceSubsystemDescriptor>
TrackingSubsystem<XRFace, XRFaceSubsystemDescriptor>
XRFaceSubsystem
Inherited Members
Namespace: UnityEngine.XR.ARSubsystems
Syntax
public abstract class XRFaceSubsystem : TrackingSubsystem<XRFace, XRFaceSubsystemDescriptor>, ISubsystem
Remarks

This class can be used to access face tracking features in your app via accessing the generic API. It can also be extended to provide an implementation of a provider which provides the face tracking data to the higher level code.

Constructors

XRFaceSubsystem()

Constructs a face subsystem. Do not invoked directly; call Create on the XRFaceSubsystemDescriptor instead.

Declaration
public XRFaceSubsystem()

Properties

currentMaximumFaceCount

Get the maximum number of faces the provider will simultaneously track.

Declaration
public int currentMaximumFaceCount { get; }
Property Value
Type Description
Int32

provider

The provider created by the implementation that contains the required face tracking functionality.

Declaration
protected XRFaceSubsystem.Provider provider { get; }
Property Value
Type Description
XRFaceSubsystem.Provider

requestedMaximumFaceCount

Get or set the maximum number of faces to track simultaneously.

Declaration
public int requestedMaximumFaceCount { get; set; }
Property Value
Type Description
Int32
Exceptions
Type Condition
ArgumentOutOfRangeException

Thrown if the requested maximum face count is less than one. To stop face tracking, call Stop().
NotSupportedException

Thrown if the requested maximum face count is greater than one but the subsystem does not support tracking multiple faces.

supportedFaceCount

Get the number of faces the subsystem is able to track simultaneously in its current configuration.

Declaration
public int supportedFaceCount { get; }
Property Value
Type Description
Int32

Methods

CreateProvider()

Creates an instance of an implementation-specific XRFaceSubsystem.Provider.

Declaration
protected abstract XRFaceSubsystem.Provider CreateProvider()
Returns
Type Description
XRFaceSubsystem.Provider

An implementation of the XRFaceSubsystem.Provider class.

GetChanges(Allocator)

Get the changes (added, updated, and removed) faces since the last call to GetChanges(Allocator).

Declaration
public override TrackableChanges<XRFace> GetChanges(Allocator allocator)
Parameters
Type Name Description
Allocator allocator

An Allocator to use when allocating the returned NativeArrays.
Returns
Type Description
TrackableChanges<XRFace>

TrackableChanges<T> describing the faces that have been added, updated, and removed since the last call to GetChanges(Allocator). The caller owns the memory allocated with Allocator.
Overrides
UnityEngine.XR.ARSubsystems.TrackingSubsystem<UnityEngine.XR.ARSubsystems.XRFace, UnityEngine.XR.ARSubsystems.XRFaceSubsystemDescriptor>.GetChanges(Unity.Collections.Allocator)

GetFaceMesh(TrackableId, Allocator, ref XRFaceMesh)

Get the mesh data associated with the face with faceId. The faceMesh is reused if it is the correct size, otherwise, it is disposed and reallocated using allocator.

Declaration
public virtual void GetFaceMesh(TrackableId faceId, Allocator allocator, ref XRFaceMesh faceMesh)
Parameters
Type Name Description
TrackableId faceId

The TrackableId for a XRFace.
Allocator allocator

The allocator to use for the returned data if a resize is necessary. Must be Allocator.TempJob or Allocator.Persistent.
XRFaceMesh faceMesh

The container for the mesh data to either re-use or re-allocate.
Exceptions
Type Condition
InvalidOperationException

Thrown if allocator is Allocator.Temp
InvalidOperationException

Thrown if allocator is Allocator.None

OnDestroyed()

Destroy the face subsystem.

Declaration
protected sealed override void OnDestroyed()
Overrides
UnityEngine.XR.ARSubsystems.XRSubsystem<UnityEngine.XR.ARSubsystems.XRFaceSubsystemDescriptor>.OnDestroyed()

OnStart()

Start the face subsystem, i.e., start tracking faces.

Declaration
protected sealed override void OnStart()
Overrides
UnityEngine.XR.ARSubsystems.XRSubsystem<UnityEngine.XR.ARSubsystems.XRFaceSubsystemDescriptor>.OnStart()

OnStop()

Stop the subsystem, i.e., stop tracking faces.

Declaration
protected sealed override void OnStop()
Overrides
UnityEngine.XR.ARSubsystems.XRSubsystem<UnityEngine.XR.ARSubsystems.XRFaceSubsystemDescriptor>.OnStop()